The present invention relates to systems that allow a user to edit 3-D reconstructions of medical diagnostic ultrasonic imaging information in a fast and efficient manner.
It is known in the art to collect 3-D ultrasound datasets. Typically, such datasets represent a regular volume, such as a cuboidal space, by way of example. Generally, the region of interest (ROI) occupies a region near the center of the cuboidal dataset and does not possess a simple geometry. A fetal face can be taken as one example of a region of interest.
Ultrasound B-mode image information is inherently difficult to segment, i.e., to separate one tissue type from another. For this reason, it is common to find the ROI obscured by tissue surrounding the ROI. This surrounding tissue is inherent in the 3-D ultrasound dataset because of its generally regular 3-D shape.
In theory, it may be possible to minimize this problem by controlling the acquisition of the 3-D ultrasound dataset so that no object other than the desired ROI is acquired. However, this is quite difficult to accomplish in practice, and in many situations is practically impossible. In any case, this approach requires considerable skill and patience on the part of the ultrasound operator.
Another prior-art approach is to edit the 3-D ultrasound dataset manually by moving a cursor in 3-D space and by using the cursor to define the unwanted tissue segments. These unwanted tissue segments are then deleted from the ultrasound dataset. This process requires considerable skill and patience. It can also be frustrating, since it is possible to delete the wrong parts of the 3-D ultrasound dataset and then to have to redo the process.
Another prior-art approach is to provide the user with an electronic scalpel to facilitate editing, as disclosed by T. R. Nelson, et al. in xe2x80x9cInteractive electronic scalpel for extraction of organs from 3-D US data,xe2x80x9d xe2x80x9cRadiology 197, 191 (1995).
Difficulties in editing 3-D datasets may result in reduced clinical acceptance of 3-D ultrasound imaging. For example, one prior-art approach requires manual editing that can easily take over an hour per 3-D dataset and per region of interest.
By way of introduction, one preferred embodiment described below displays a 3-D reconstruction of a 3-D ultrasound image dataset in combination with an editing object. The editing object defines a line, curve or surface, and the user can move the editing object in an intuitive manner relative to the 3-D reconstruction using a controller having six degrees of freedom. This system automatically edits the 3-D reconstruction to reduce the opacity of a portion of the 3-D reconstruction on a selected side of the editing object. The user can repeatedly position the editing object to remove undesired portions of the 3-D reconstruction, thereby revealing the desired region of interest.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims.